CLAIM The ornamental design for a gearbox for an electric motor, as shown and described.

Description:

FIG. 1 is a perspective view of a gearbox for an electric motor showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a rear elevational view thereof.

The broken lines shown are for illustrative purposes only and form no part of the claim. Where broken lines abut a claimed surface it is understood that those broken lines represent an unclaimed boundary between claimed and unclaimed surfaces. None of the broken lines form any part of the claimed design.